They're a pop rock band, influenced by punk, metal and rap.
They never claimed to be 'punk' so all you petty losers can stop your bitching.
Just because a band has an army of teeny fans doesn't detract from the fact that their music is actually...pretty damn good.

SUM 41 is a commercially driven modern rock band created by someone or a group of people who choose to use bright colors and flashy lights in videos and on people as a vehicle for their advertising. Ideal MTV band.